Thursday, October 15, 2015

Outdoor Lights Don't Deter Crime

There, I said it. Bear with me. I'll walk back that counter-intuitive statement in a bit. But only a little.

Regularly I read on Facebook or Nextdoor or in chain emails a call for everyone to keep their porch lights on overnight. Or for the city to install more street lights. The following is a typical example:

Some people regularly turn porch lights off when going to bed. I'm always amazed driving through neighborhoods and no exterior lights are on. It's one little thing we can do to maybe deter a crime. Having a well lit exterior just sends a signal that we care and are watching.

Source: Facebook.

This is repeated so often that most people just assume it must be good advice. I, on the other hand, have never been convinced of the logic of this. I've suspected that street lighting might even do more harm than good. But I didn't have the facts. Now I do.
And although the facts don't support my skepticism, they don't support the conventional wisdom either. CityLab has the numbers.

According to a 2007 systematic review of lighting experiments in American cities, increased street lighting in Indianapolis, Harrisburg, New Orleans, and Portland, Oregon, did not coincide with a drop in the affected areas' crime rates, but it did in Atlanta, Milwaukee, Kansas City, and Fort Worth. Yet even in U.S. cities where lights "worked," they didn't appear to work consistently: While Fort Worth saw a decrease in all types of crime, Kansas City saw a decrease only in violent crime.

Street lights enable criminals as much as they do their potential victims, according to criminologist Ken Pease. With increased street-lighting, potential thieves have an easier time seeing the contents of parked cars, don't need to carry flashlights (which could alert someone to their presence), and are able to case a place and determine if there's anyone around who can impede their break-in. The light may scare criminals away, but it can also tell them enough about a house or a street or a parking lot to know whether there's anything for them to be scared of.

This always made a lot of sense to me. Think about it. If you have to go outside at night (to get the mail, set out the trash, bring in the dog) what do you do first? Turn on a light. Light makes your task easier. In fact, someone wandering around your property in the dark, especially with a flashlight, is more likely to attract suspicion than someone walking around with the lights on. While the homeowner is inside fast asleep, the outdoor lights just make a thief's job easier.

So, if you're going to flood your yard with lights overnight, or ask the city to install more street lights, make sure the lights are telling the potential criminals the right story. Shine your light on your "Beware of Dog" sign. Shine your light on your security camera. Remove anything worth stealing from your car or yard, then shine your light on the emptiness that remains. (This last part won't work if your car has an entertainment system, or expensive wheels, or all kinds of stuff on the seats. In that case, your light just highlights the merchandise, so to speak.)

In fact, out of all of this, the most effective deterrent that involves outdoor lighting also includes a set of well-placed security cameras. Point the cameras everywhere. Then point the lights everywhere, including the cameras themselves. If this last bit leads to the thieves stealing the cameras, so be it. You just might get a close up picture of the thief in the process.